Ever since his daughter Emma started kindergarten, Garth Callaghan has been making her a lunch to take to school every day.

“I went to lunch with her at school one day,” Callaghan, from Richmond, Va., told FoxNews.com. “I actually chose to buy lunch with her, and I thought, ‘This is really not delicious.’ So we decided as a family we were going to limit the time Emma bought lunch and make lunch as much as possible.”

When Callaghan first started putting together his daughter’s lunches, he wanted to do a little something extra for her. So each day, he would write a special note on a napkin and leave it in her lunch sack.

Initially the notes started off as sketches or easy phrases she could understand, but as she grew older, the messages slowly evolved into thoughtful quotes or words of inspiration.

“The notes took on more sophistication,” Callaghan said. “I wanted her to be more supported. I really wanted to her have a strong sense of self…. So I started to search out quotes and things that were positive. I was actually spending more time putting together her napkin than putting together her lunch.”

The napkin note tradition continued as Emma grew up, and as a 13-year-old about to start high school, she still receives the notes in her lunch. But recently, the notes have taken on an entirely new meaning.

In the fall of 2011, Callaghan was diagnosed with kidney cancer and had to undergo intensive treatment and a painful surgery.

“My first cancer, my tumor was very large, and the surgery was very long,” Callaghan said. “Unbeknownst to me, my wife and my daughter were conspiring against me to not share how impacted Emma was. I thought she was taking it well, but she was really afraid and very scared, and I didn’t know that.”

One day after his surgery, Callaghan noticed Emma ripping up one of his napkins. At first he thought he had done something wrong or had written a poor note.

But the reason turned out to be something else entirely. Emma was ripping off the quote so that she could save it in a composition book. Since then, she has been saving as many of her father’s notes as she can.

“She later said that she was trying to save a piece of me,” Callaghan said.

After battling cancer three separate times over the past two years, Callaghan is officially in recovery, and doctors have told him there is currently no cancer in his body. However, his initial prognosis was only a 10 percent five-year survival rate.

Not wanting to leave Emma without her daily source of inspiration, Callaghan started working overtime, writing a stockpile of 826 napkin notes. He hopes the notes will last Emma throughout the rest of high school.

“My five-year cancer anniversary would [have been] around the same time she started college,” Callaghan said. “So I sat down and counted up how many school days she’d have lunch, and it turned out that’s 826 days, so I immediately sat down and figured out how to write out 826 napkin notes without repeats and have those set aside in the event I can’t fulfill my promise.”

While Callaghan is confident that he will be around for Emma’s graduation day, he said he still wanted to be a responsible parent in case anything ever happened to him.

“The sense of mortality is not unfounded,” Callaghan said. “I truly believe that I’m not going to die from cancer in the next five years…But there’s all sorts of things that could happen that are unplanned for. So I decided to take action just in case… That way my wife and daughter have these to read and can understand my outlooks on life in the event I’m not around to do it.”

Callaghan has posted many of his notes on his Facebook page and on napkinnotesdad.com. Many parents have also reached out to him for advice on how to better connect with their children.